Oxy-fuel combustion technology is technology that easily performs collection of carbon dioxide by injecting and combusting oxygen-fuel that removes a nitrogen component occupying about 79% of air instead of using existing combustion air in an existing air combustion method that is injected into a combustor without removing nitrogen and other components in the air. In technology that recovers carbon dioxide by adapting oxy-fuel combustion, by combusting using a high concentration of oxygen having purity of 95% or more instead of air as an oxidizing agent, heat is generated. Most of exhaust gas that is generated through oxy-fuel combustion is formed of carbon dioxide and steam, and by recirculating about 70-80% of the generated exhaust gas to a combustion chamber, a concentration of carbon dioxide of the exhaust gas may be finally concentrated to 80% or more. In the oxy-fuel combustion technology, when condensing steam as a main component of the discharged exhaust gas, almost an entire amount of carbon dioxide may be recovered, and by storing the recovered carbon dioxide, carbon dioxide and an air pollution material are not discharged.
As described above, a carbon dioxide conversion system collects a high concentration of carbon dioxide. However, for oxy-fuel combustion, a high concentration of oxygen is required, and in this case, when separating oxygen from the air using an Air Separation Unit (ASU), much energy is consumed and thus there is a drawback that entire system efficiency is lowered.
Further, in a conventional system, the system is used for collecting, transporting, and storing a high concentration of carbon dioxide that is discharged through oxy-fuel combustion and thus there is a problem that a use value is deteriorated.
Further, a conventional oxy-fuel combustor uses oxygen as an oxidizing agent and a single flame temperature is high compared with when using air, and as a combustor outer wall may be damaged thereby, in order to reduce the combustion temperature, steam is injected. In this case, there is a problem that a heat source for generating steam should exist and separate pump work for driving the steam is needed.